In recent years, studies on containerless levitation techniques as methods for producing glass materials are being conducted. For example, Patent Literature 1 describes a method for vitrifying a barium-titanium-based ferroelectric sample by heating the barium-titanium-based ferroelectric sample levitated in an aerodynamic levitation furnace to melting by irradiation with a laser beam and then cooling it. The containerless levitation techniques can reduce the progress of crystallization of a material due to contact with the wall surface of a container in the above manner and, therefore, can vitrify even materials that could not be vitrified by conventional production methods using containers. Hence, the containerless levitation techniques are noteworthy as methods enabling the production of glass materials having novel compositions.
In Patent Literature 2, a larger glass material is obtained using a containerless levitation technique in which a forming surface having a plurality of gas jet holes is used. Provision of a large-sized glass material is preferred because it increases the variety of application possibilities.